Rotary straightener



June 8, 1965 M. W. ZOLTON ROTARY STRAIGHTENER 2 Sheets-Sheet 1 Filed NOV. 20, 1961 /W/cae/ l/V. Za/zof? INVENToR.

BY 7% fg Arron/vf y June 8, 1965 Filed Nov. 20, 1961 M. W. ZOLTON ROTARY STRAIGHTENER 2 Sheets-Sheet 2 M26/706V l/V. Zo/of? INVENTOR.

United States Patent Cfice 3,187,536 Patented `Iuine 8, 1F65 3,187,536 RQTARY STRAIGHTENER Michael W. Zeiten, Houston, Tex., assigner to Pritchett Engineering d: Machine, Inc., Houston, Tex., a corporation of Texas Filed Nov. 20, 1961, Ser. No. 153,657 Claims. (Cl. 72-99) This invention relates to a rotary straightener, and more particularly it relates to vapparatus for straightening relatively long cylindrical members including both solid and tubular members.

In the manufacture of cylindrical members, almost any manufacturing method known produces members which are unsatisfactory for many applications because of a lack of sutiicient straightness. Some applications of shafting, for example, require that the shafting shall be straight with 0.0015 inch or less eccentricity per foot of length. In order to produce such straight shafting, or other cylindrical members, machines have heretofore been devised which, with varying effectiveness, improve the straightness of such members, Machines heretofore used have, however, been deficient in some respects. It is one of the objects of this invention to provide a straightening machine in which the deficiencies of machines previously used are overcome.

For example, straightening machines previously used have had a tendency to leave` the member being straightcned with a small, short curved portion or hook on its end. It is an object of this invention to provide a straightening machine which has means for eliminating such an end hook.

Members straightened by previous straightening machines have also had a tendency to gradually become more crooked after a period of time, as stressesrput into the member during the straightening process relieve themselves. It is an object of this invention to provide a straightening machine in which stresses imposed on the member being s-traightened are substantially uniform throughout the length and circumference of the member, so that as stresses are relieved during aging, they are relieved substantially uniformly so as not to result in reduction of the straightness of the member.

These and other objects of the invention will become more apparent upon consideration of the following description and the accompanying drawings, in which FIGURE l is a front elevational view of one embodiment of the straightening machine of this invention;

FIGURE 2 is a right end elevational view of the embodiment of FIGURE l;

FIGURE 3 is a horizontal sectional view taken at line 3 3 of FIGURE l;

FIGURE 4 is a horizontal sectional view taken at line 4 4 of FIGURE l;

FIGURE 5 is a fragmentary View of a portion of the embodiment of FIGURE l, parts being shown in section;

FIGURE 6 is a fragmentary view of a portion of the structure shown in FIGURE 5;

FIGURE 7 is a fragmentary vertical sectional view of a portion of the structure shown in FIGURE 3, taken at line 7-7 of FIGURE 3; and

FIGURE 8 is a horizontal sectional view of the portion shown in FIGURE 7, taken at line 8-8 of FIG- URE 7.

Briefly, the rotary straightener of this invention comprises a main frame on which are mounted a plurality of upper and lower rolls between which the element to be straightened is passed. The rolls are each rotated so as to feed the element through the machine and simultaneously rotate the element. The rolls are formed in a shape which allows each roll to make line contact with the element as the element feeds through the machine. The rolls are placed at an angle with respect to the direction of travel of the element, and this angle is adjustable so as to provide line contact with elements of various diameters. The upper rolls are also adjustable vertically so that different diameters may be accommodated. The longitudinal spacing of both upper and lower rolls is normally other than equidistant, for a reason which will be explained hereinafter.

Referring now to FIGURE 1, the main frame 10 has rigidly attached thereto on the left end, as seen in FIG- URE 1, a motor mounting frame 14. Mounted on frame 14 is a motor 36 and a gear unit 38, to the input shaft of which the motor 36 is coupled. Gear unit 3S has three output shafts 40, 42, and 44, which are coupled by means of universal joints 46 to telescoping shafts 48, 5t), and 5 2. The telescoping shafts are in turn coupled at their other ends, through additional universal joints 46, to lower rolls 54, 56, and S8 respectively.

Suspended from the upper portion of the frame 10, by means to be hereinafter described, are a plurality of upper rolls 18, 20, 22 and 24. Means are provided for rotatably driving these upper rolls. Such means may comprise fluid motors 16. The axes of all of the rolls, both upper and lower, lie substantially in parallel planes, shown as horizontal in the drawing, and are at substantially the same angle to the line of travel 26 (FIGURE 4) of the member to be straightened, shown in broken line at 28 in FIGURE l.

Each of the 4lower r-olls is rotatably mounted in a saddle 60, which is in turn pivotally mounted for pivoting in a horizontal plane of a bearing 62 (see FIGURE 7). Saddle 60 is provided with a stub shaft 64 about whose axis the saddle is pivotable. Shaft 64 has rigidly attached to its lower end a segment of a Worm Wheel 66 which is in operable engagement with a worm 68, mounted on a worm shaft 70.

It is apparent from FIGURE 1 that Worm shaft 70 extends longitudinally of the apparatus of this invention, and has mounted thereon a worm 68 for each saddle 60. Worm shaft 70 has a square cross-section end 72 on which a crank may be positioned. The rotation of such a crank will cause the worms 68 to rotate, and thus, because of the engagement of these Worms with worm wheel segments 66, cause simultaneous pivoting of each saddle 66, so that each of lower rolls 54, 56, and 5S is always positioned at the same angle with the line of travel of the element being straightened.

Upper rolls 18, 20, 22, and 24 may also be pivoted to various angles with respect to the line of travel of the element being straightened. In addition, these upper rolls are adjustable vertically, so lthat the apparatus can accommodate a broad range of diameters of cylindrical elements to be straightened. The means for providing simultaneous vertical and angular positioning of the upper rolls are shown in FIGURE 5. Here it will be seen that a cartridge 74 has rotatably mounted therein a jack-shaft 76. On the upper end of jack-shaft 76 a fluid motor 78 or other motive means is provided for rotation of shaft 76. Shaft 76 is threadedly received in a sleeve 80, which is slidably mounted within cartridge 74. The lower end of sleeve 80 is provided with a flange 82 to which a saddle 84 is attached. Saddle 84 has rotatably mounted therein one of the upper rolls, shown in FIG- URE 5 as 24.

As shown in FIGURE 6, sleeve 80 has in its wall a cam slot 86, in which a cam 88 is positioned. Cam 8S is fixed in the wall of cartridge 74. It will be seen, therefore, lthat upon rotation of shaft 76 by motor 78, sleeve 8G will be caused to move vertically, and also to pivot about its vertical axis, because of the action of the cam 88 on the cam slot 86. Thus the upper rolls are pivoted art.

Si to change the angle of their axes with respect to the axis of the member being straightened.

The rolls used in the apparatus of this invention are in the general form of a hyperboloid of one sheet, so that the working surface of a roll has straight-line elements. Thus as a cylindrical member to be straightened is fed through the rolls, the rolls make line contact with the member, regardless of the members diameter.V Physical limitations do, of course, provide upper and lower limits on the size of cylindrical member which can be straightened, but the apparatus of this invention may readily be constructed to provide straightening of cylindrical members having diameters within a range of several inches.

The angle at which the rolls are set with respect to the axis of the member being straightened must be changed for different diameters of members. The largest diameter member to be straightened requires the largest angle between the roll axis and the member axis, whereas the smallest diameter member to be straightened determines the smallest angle required between the roll axis and the member axis. The calculation of these angles for various diameter members will be apparent to those skilled in the After calculation, the combinations of diameters and angles are used in determining the shape of the cam slot 86 shown in FIGURE 6. As has previously been explained this cam slot causes pivoting of the upper roll as it is moved vertically to accommodate various diameters of members to be straightened. The heretofore described apparatus shown in detail in FIGURES 7 and 8 is used to pivot the lower rolls lto the proper angle.

If the member to be straightened is fed into the machine from the right side, as shown in FIGURE 1, the member will first be passed between terminal rolls 24 and 58. These two rolls are spaced apart at their midpoints, or throats, just enough to pass the member between them and to impart a longitudinal and rotational motion to the member. As the member progresses longitudinally through the machine, it will come into contact with upper roll 22. This axis of roll 22 is slightly lower than that of roll 24, so that when the member is passed under roll 22, it is'deilected downwardly enough to exceed the yield point of the material of the member. The member is then fed longitudinally into contact with lower roll 56. This roll is positioned vertically so as to deflect the member upwardly, again sufficiently to exceed the yield point, and may be slightly higher than roll 58. Upper roll is again low enough 4to deflect the member downwardly to exceed the yield point. Upper roll 18 and lower roll 54 are positioned on the same axes as upper roll 24 and lower roll 58, respectively, so that upon passing between rolls 18 and 54, the member is brought back to the original line of travel 26. It will be apparent that as the member progresses longitudinally through the machine, it is also caused to rotate, because of the force of the powered rolls on it. The contacting of the surface of the member by the rolls, particularly the intermediate rolls which deflect the member, results in a cold working of this surface, which produces stresses in the member. Since the member is both rotating and moving longitudinally, and each roll makes line contact with the member, the portion of the surface of the member in which stresses are produced by any one roll is in the form of a helical band, having a width equal to the length of the line contact between the roll and the member. According to this invention, the helical bands of cold worked surface produced by the several intermediate rolls are positioned so that they overlap, so that the entire surface of the member is cold worked substantially uniformly. Thus the stresses set up in the surface of the member during the cold working are distributed substantially uniformly over the surface of the member. It will be appreciated that after the straightening process is completed, and the cylindrical members are stored or otherwise disposed of, the stresses produced by the cold working will begin to slowly relieve themselves. If the stresses are not substantially uniformly distributed over the surface of the member, the relieving of the stress will cause the member to become deformed.

It has been found that an odd-numbered plurality, i.e., at least three, intermediate deflecting rolls are required for maximum eliiciency in straightening. These are preferably spaced alternately, not opposite each other, along the line of travel of the member, with the last intermediate roll on the same side of the line as the first intermediate roll.

An important feature of this invention is that the distance between intermediate rolls 26 and 22 is different from the distance between either terminal roll 18 or 24 and the adjacent intermediate roll. It will be recognized that as a cylindrical element to be straightened is fed through the rolls, the element will tend to Whip, because it is bent as it passes over each roll. If the rolls were all spaced equally, this whip or oscillation of the element would be accentuated at each roll. If allowed to continue, such oscillation would set up a standing wave in the element, which would deform it, thereby preventing straightening of the element. The unequal spacing of the rolls, however, tends to dampen the oscillation.

Thus two factors are taken into consideration in determining the spacing of the rollers with respect to each other. Firstly, the spacing must be unequal so as to dampen the eifect of whipping or oscillation of the member during the straightening process, and, secondly, the spacing must be such as to insure that the entire surface of the member is cold-worked. It will be apparent that the magnitude of the stresses imparted to the member is dependent upon the force applied to the member by each of the rolls, and that this force is in turn dependent upon the vertical position of each'roll with respect to the line of travel of the surface of the member, or, in other words, upon the amount of bending of the member caused by each roll. This vertical position, or amount of bending, will of course vary considerably, depending upon the diameter of the member, the form of the member, and the yield strength and resiliency of the material from which the member is made. These factors are preferably taken into account in designing the cam slot 86.

It will be noted that upper roll 24 and lower roll 58, comprising terminal rolls at the inlet to the machine, are directly opposite one another, so as to confine the cylindrical member as it is fed into the machine. Again, upper roll 18 and lower roll 54, comprising terminal rolls at the outlet of the machine, are directly opposite each other, so as to conne the cylindrical member as it leaves the machine. This feature of the construction of this invention prevents whipping of the member as it feeds into or exits from the machine. If such confining means is not employed, one or both ends of the member would end up with a tail-end hook or curve, caused by the whipping action.

The apparatus of this invention is capable of straightening externally upset members, i.e. members which have an enlarged diameter at one or both ends, as well as members which have substantially the same diameter throughout their lengths. In the case of externally upset members, the terminal rolls are spaced vertically apart a distance substantially equal to the diameter of the upset portion. When the member is fed between these terminal rolls, these rolls carry it into engagement with the 'first intermediate roll. This roll is positioned so as to engage the upset portion and exert a bending force on the member, bending it against the terminal roll on the opposite side of the member. Then as the upset portion is fed on to engage the next intermediate roll, this roll bends the member in the opposite direction against the rst intermediate roll. Vertical and longitudinal spacing of the rolls is adjusted as necessary to obtain the required bending and cold working of the member.

The combination of the terminal confining rolls with an odd-numbered plurality of intermediate deflection rolls, Yeach of which deflects a different area of the member being straightened, insures accurate straightening of` the member. Many modifications of the specic embodiment shown and described herein will be apparent to those skilled in the art, therefore the invention is not limited thereto, but only as defined by the following claims.

I claim:

1. Apparatus for straightening` cylindrical members comprising a plurality of upper and lower rolls spaced along the line of travel of the cylindrical member through the apparatus and at an angle to said line of travel,

whereby said member may be passed longitudinally between and in contact with each of said upper and said lower rolls, t

each of said rolls having a contour which is generally in the form of a hyperboloid of one sheet, andthe longitudinal spacing between at least some of said rolls being different from the longitudinal spacing between others of said rolls by an amount sufficient to inhibit the generation of a standing wave in the member t'o be straightened.

2. Apparatus for straightening cylindrical members during movement of such members longitudinally through said apparatus comprising a frame having an inlet end and an outlet end,

a plurality of upper and lower rolls contoured generally in the form of a hyperboloid of one sheet mounted on said frame and spaced along the line of travel of the member to be straightened,

one of said upper rolls and one of said lower rolls comprising terminal rolls positioned opposite each other at the inlet end,

another or said upper rolls and another of said lower rolls comprising terminal `rolls positioned opposite each other at the outlet end,

each of said rolls being positionable at such an angle to said line of travel and at such a vertical elevation with respect to said line of travel and the diameter of the member as to provide line contact of each of said rolls with said member, and the longitudinal spacing between at least some of said rolls being different from the longitudinal spacing between others of said rolls by an amount sufiicient to inhibit the generation of a standing wave in the member to be straightened.

3. Apparatus as deiined by claim 2 and including means for simultaneously varying the elevation and the angle of the upper rolls to conform to differentV diameter members.

4. Apparatus as detined by claim Z and including means for varying the angle of the rolls with respect to the line of travel. t

5. Apparatus as defined by claim 2 and including an odd-numbered plurality of alternate upper and lower rolls intermediate said terminal rolls spaced along said line of travel.

6. Apparatus as defined by claim 5 in which each of saidY intermediate rolls is positioned to deflect said member from said line of travel.

7. Apparatus as defined by claim 6 and including motor means for rotating each of said rolls about its axis, whereby said rolls cause rotation and longitudinal movement of said member.

8. Apparatus for straightening cylindrical members comprising the' axis of each of said rolls being horizontal and at an angle to`- the said line,

motor means for rotating each of said rolls about its axis,

one of said upper `rolls and one of said lower rolls comprising terminal rolls positioned opposite each other at the inlet end of the frame,

another of said upper rolls and another of said lower rolls comprising terminal rolls positioned opposite each other at the outlet end of the frame,

the remainder of said lrolls comprising an odd-numbered plurality of alternate upper and lower rolls intermediate said terminal rolls,

means forl simultaneously varying the elevation and the angle' o'f the upper rolls to provide line contact thereof with members of different diameter,

and means for varying the angle of the lower rolls to provide lin'e contact thereof with members of difterent diameter whereby the upper and lower rolls may be moved to such a position that all of said rolls contact said member and a combined rotary and longitudinal motion is imparted to said member, so that the portions contacted by each roll constitute a helical band around said member, the spacing of said rolls being such that all portions of the surface of said member are contacted by rolls.

9. Apparatus for straightening cylindrical members comprising a frame having an inlet end and an outlet end,

a plurality of upper rolls and lower rolls spaced along and positioned respectively above and below a line extending from said inlet end to said outlet end, said line forming the line of travel through the apparatus of a member being straightened,

the surface of each of said rolls being formed generally in the form of a hyperboloid of one sheet,

the axis of each of said rolls being substantially horizontal and at an angle to the said line,

and motor means for rotating each of said rolls about its axis,

one of said upper rolls and one of said lower rolls comprising terminal rolls positioned opposite each other at the inlet end of the frame,

and another of said upper rolls and another of said lower rolls comprising terminal rolls positioned opposite each other at the outlet end of the frame, the longitudinal spacing between at least some of said rolls being different from the longitudinal spacing between others of said rolls by an amount suflicient to inhibit the generation of a standing wave in the member to be straightened.

10. In an apparatus for straightening cylindrical members wherein the members are passed longitudinally between upper and lower rolls set at an angle to the line of travel of the member so as to simultaneously rotate the member and move the member longitudinally while defleeting the member from the line of travel, and wherein the surface of each of the said rolls is in the form of a hyperboloid of one sheet, the improvement which comprises means for simultaneously varying the distance between each upper and lower roll and varying the angle of one of said upper and lower roll an amount required to maintain line contact thereof with a member having a diameter equal to the distance between said upper and lower roll.

11. Apparatus as defined by claim 10 wherein one of said upper rolls and said lower rolls are mounted on a housing which is rotatable in a plane whereby said angle is varied and is axially movable in a direction whereby said distance is varied, and including means engaging said housing to cause simultaneous rotation and axial movement automatically proportioned to maintain said line contact.

12. Apparatus as defined by claim 11 wherein said 13. Apparatus for straightening cylindrical members during movement of such members longitudinally through said apparatus comprising a frame having an inlet end and an outlet end;

a plurality of upper and lower rolls each contoured generally in the form of a hyperboloid of one sheet mounted on said frame and spaced along the line of travel of the member to be straightened, said rolls including an upper roll and a lower roll comprising terminal rolls positioned opposite each other at the inlet end,

an upper roll and a lower roll comprising terminal rolls positioned opposite each other at the outlet end,

an odd-numbered plurality of alternate upper and lower rolls intermediate said terminal rolls and spaced along said line of travel,

each of said rolls being positioned at such an angle and at such a vertical elevation as to provide line contact of each of said rolls with said member,

the position of each intermediate roll with respect to the other rolls and with respect to the line of travel of the member being such as to impart a bending force to the member sufficient to exceed the yield point of the material of the member, and the longitudinal spacing between each terminal roll and the adjacent intermediate roll being different from the longitudinal spacing between adjacent terminal rolls. 14. Apparatus as dened by claim 13 and including means for varying the positions of the rolls to conform l() to dicerent diameter members.

15. Apparatus as delned by claim 13 and including motor means for rotating each of said rolls about its axis, whereby said rolls cause rotation and longitudinal movement of said member.

References Cited by the Examiner UNITED STATES PATENTS 613,754 11/98 Brightman 153-105 1,119,044 12/14 Sargent et al 153-105 20 2,334,886 11/43 Siegrist 153-108 2,838,090 6/58 Skawden et al. 153-108 XR 2,987,096 6/ 61 McConnell 153-108 CHARLES W. LANHAM, Primary Examiner. 

1. APPARATUS FOR STRAIGHTENING CYLINDRICAL MEMEBRS COMPRISING A PLURALITY OF UPPER AND LOWER ROLLS SPACED ALONG THE LINE OF TRAVEL OF THE CYLINDRICAL MEMBER THROUGH THE APPARATUS AND AT AN ANGLE TO SAID LINE OF TRAVEL, WHEREBY SAID MEMBER MAY BE PASSED LONGITUDINALLY BETWEEN AND IN CONTACT WITH EACH OF SAID UPPER AND SAID LOWER ROLLS, EACH OF SAID ROLLS HAVING A CONTOUR WHICH IS GENERALLY IN THE FORM OF A HYPERBOLOID OF ONE SHEET, AND THE 